USGS HVO image shows Moku‘āweoweo, the caldera at the summit of Mauna Loa, from video taken during a routine overflight.

Weekly Mauna Loa Volcano Activity Updates Begin

by Big Island Video News
on Jul 11, 2019 at 5:01 pm

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STORY SUMMARY

HAWAIʻI ISLAND - After the Mauna Loa alert level was elevated to ADVISORY last week, the USGS Hawaiian Volcano Observatory is now publishing an update, once-per-week.

(BIVN) – Mauna Loa Volcano is not erupting, although the USGS Volcano Alert level for was changed from NORMAL to ADVISORY on July 2.

“For the past several months, earthquake and ground deformation rates at the volcano have exceeded long-term background levels,” a weekly update from the USGS Hawaiian Volcano Observatory stated. “This increase in alert level does not mean that an eruption is imminent nor that progression to an eruption is certain. A similar increase in activity occurred between 2014 and 2018 and no eruption occurred.”

Since the alert level was raised, updates on the status of Mauna Loa Volcano are now being issued each week, on Thursdays, until further notice. Today was the first.

The slightly elevated rates of deformation and seismicity on Mauna Loa have not changed significantly in the past week.

From the USGS HVO weekly update:

During the past week, approximately 95 small-magnitude earthquakes (less than M2.0) occurred beneath the summit and flanks of the volcano, compared to ~115 earthquakes the week before. Most earthquakes occurred at depths of less than 5 km (3 miles). Additional deeper seismicity at depths less than 10 km (6 miles) was primarily scattered beneath the southwest flank of the volcano.

Seismicity remains elevated, with an average of at least 50 shallow small-magnitude earthquakes per week following an earthquake swarm in October 2018. This compares to a rate of fewer than 20 earthquakes per week beneath the volcano in the first half of 2018.

Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements show continued summit inflation, suggestive of renewed recharge of the volcano’s shallow magma storage system. This rate of inflation has not changed since the alert level was raised on July 2nd, 2019, and remains consistent with increased rates of inflation following the October 2018 earthquake swarm.

No significant changes in volcanic gas release at Sulphur Cone on the Southwest Rift Zone were measured. Fumarole temperatures at both Sulphur Cone and at the summit remain unchanged.